Current Interrupt Device and Battery Module Including the Same

ABSTRACT

A current interrupt device, which may be included in a battery module, includes first and second connection parts each having one surface on which an inclined surface is formed; wherein the inclined surface of the first connection part and the inclined surface of the second connection part contact each other to form a contact interface, the first connection part and the second connection part are electrically connected to each other, and when an external force equal to or greater than a predetermined force is applied to the inclined surface of the first connection part or the inclined surface of the second connection part, the inclined surface of the first connection part and the inclined surface of the second connection part are dislocated with respect to each other on the contact interface to interrupt electrical connection between the first connection part and the second connection part.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a national phase entry under 35 U.S.C. § 371of International Application No. PCT/KR2018/015200, filed Dec. 3, 2018,which claims the benefit of the priority of Korean Patent ApplicationNo. 10-2018-0017174, filed on Feb. 12, 2018, both of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a current interrupt device and abattery module including the same, and more particularly, to a currentinterrupt device that is capable of improving safety of a battery moduleand a battery module including the same.

BACKGROUND ART

As demands of secondary batteries, which are repeatedly chargeable anddischargeable, increase, the importance of safety of secondary batteriesis also increasing. For example, an increase of a capacity per unitvolume of a secondary battery is required. As the capacity per unitvolume of the secondary battery increases, safety of the secondarybattery tends to be more vulnerable. Thus, the safety of the secondarybattery needs to be improved as well as the capacity of the secondarybattery. Particularly, when a lithium secondary battery is overcharged,a risk of ignition of the lithium secondary battery increases. Thus, itis essential to secure the safety in the lithium secondary battery.

According to the related art, in order to solve the problem of theignition within the secondary battery, a technique of adding ananti-ignition material or the like to an electrolyte that is charged inthe secondary battery is being used, or a technique of mounting a devicesuch as a current interrupt device (CID) within the secondary battery isbeing used.

However, the safety devices of the secondary battery according to therelated art are constituents for securing the safety of one secondarybattery. Thus, in the case of a battery module in which a plurality ofsecondary batteries is assembled, there is a problem that the safety ofthe battery module is limited by only the safety device according to therelated art.

For example, in the case of the battery module, since the secondarybatteries are electrically connected to each other, a temperature of theentire battery module rapidly increases due to electrical interactionbetween the secondary batteries. Thus, it is necessary to secure safetyin an aspect of the battery module separately from the individual safetyof the secondary battery.

DISCLOSURE OF THE INVENTION Technical Problem

To solve the above problem, an object of the present invention is toimprove safety of a battery module by preventing ignition that may occurdue to electrical interaction between secondary batteries in the batterymodule from occurring.

Technical Solution

According to one aspect of the present invention, a current interruptdevice includes: a first connection part having one surface on which aninclined surface is formed; and a second connection part having onesurface on which an inclined surface having a shape corresponding to theinclined surface of the first connection part is formed, wherein theinclined surface of the first connection part and the inclined surfaceof the second connection part contact each other to form a contactinterface, the first connection part and the second connection part areelectrically connected to each other, and when an external force equalto or greater than a predetermined force is applied to the inclinedsurface of the first connection part or the inclined surface of thesecond connection part, the inclined surface of the first connectionpart and the inclined surface of the second connection part aredislocated with respect to each other on the contact interface tointerrupt electrical connection between the first connection part andthe second connection part.

The current interrupt device may further include an adhesion partdisposed on the contact interface so that the inclined surface of thefirst connection part and the inclined surface of the second connectionpart adhere to each other.

The current interrupt device may further include a pressing partdisposed above or below the first connection part and the secondconnection part to press the first connection part and the secondconnection part downward or upward, respectively.

The current interrupt device may further include a support partsupporting the pressing part so that the pressing part presses the firstconnection part and the second connection part.

The current interrupt device may further include an upper pressing partmay be disposed above the first connection part and the secondconnection part that presses the first connection part and the secondconnection part downward, and a lower pressing part may be disposedbelow the first connection part and the second connection part thatpresses the first connection part and the second connection part upward.

The current interrupt device may further include a first fixing partdisposed on an outer portion of the first connection part so that thefirst connection part is configured to be coupled to a portion of acircumferential portion of a first secondary battery, and a secondfixing part disposed on an outer portion of the second connection partso that the second connection part is configured to be coupled to aportion of a circumferential portion of a second secondary battery.

The current interrupt device may further include a pressing partdisposed above or below the first connection part and the secondconnection part to press the first connection part and the secondconnection part downward or upward, respectively, wherein the sum ofadhesion strength of the adhesion part and an elastic modulus of thepressing part may be 2 kgf/cm to 5 kgf/cm.

According to another aspect of the present invention, a battery moduleincludes: a first battery; a second battery spaced apart from the firstbattery; and a current interrupt device disposed between the firstbattery and the second battery, wherein the current interrupt deviceincludes: a first connection part having one surface on which aninclined surface is formed; and a second connection part having onesurface on which an inclined surface having a shape corresponding to theinclined surface of the first connection part is formed, wherein theinclined surface of the first connection part and the inclined surfaceof the second connection part contact each other to form a contactinterface, the first connection part and the second connection part areelectrically connected to each other, and when an external force equalto or greater than a predetermined force is applied to the inclinedsurface of the first connection part or the inclined surface of thesecond connection part, the inclined surface of the first connectionpart and the inclined surface of the second connection part aredislocated with respect to each other on the contact interface tointerrupt electrical connection between the first connection part andthe second connection part.

Advantageous Effects

According to the present invention, the ignition that may occur due tothe electrical interaction between the secondary batteries in thebattery module may be prevented to improve the safety of the batterymodule.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a first example of a structureof a current interrupt device in a state in which a battery modulenormally operates according to the present invention.

FIG. 2 is a perspective view illustrating a principle of interruptingcurrent by the current interrupt device according to the first examplewhen the battery module is overcharged.

FIG. 3 is a perspective view illustrating a second example of astructure of a current interrupt device in a state in which a batterymodule normally operates according to the present invention.

FIG. 4 is a perspective view illustrating a principle of interruptingcurrent by the current interrupt device according to the second examplewhen the battery module is overcharged.

FIG. 5 is a perspective view illustrating a third example of a structureof a current interrupt device in a state in which a battery modulenormally operates according to the present invention.

FIG. 6 is a perspective view illustrating a principle of interruptingcurrent by the current interrupt device according to the third examplewhen the battery module is overcharged.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a structure of a current interrupt device according to thepresent invention will be described with reference to the accompanyingdrawings.

Current Interrupt Device

FIG. 1 is a perspective view illustrating a first example of a structureof a current interrupt device in a state in which a battery modulenormally operates according to the present invention.

As illustrated in FIG. 1, a battery module 10 according to the presentinvention may include a plurality of batteries 100. The plurality ofbatteries 100 may be secondary batteries, for example, lithium secondarybatteries. In FIG. 1, a first battery 110 and a second battery 120 areillustrated as constituents of the plurality of batteries 100. However,the battery module 10 may include three or more batteries. A lead 200may be provided in each of the plurality of batteries constituting thebattery module according to the present invention. FIG. 1 illustrates acase in which a first lead 210 and a second lead 220 are respectivelyprovided in the first battery 110 and a second battery 120.

A current interrupt device 300 may be provided between the first battery110 and the second battery 120.

As illustrated in FIG. 1, the current interrupt device 300 according tothe first example of the present invention may include a plurality ofconnection parts including an inclined surface. That is, as illustratedin FIG. 1, the current interrupt device 300 according to the firstexample of the present invention may include a first connection part 302having one surface on which an inclined surface SL (see FIG. 2) isformed and a second connection part 304 having an inclined surfacecorresponding to the inclined surface of the first connection part 302.Here, that the inclined surfaces correspond to each other may mean thatthe inclined surfaces face each other. Also, the inclined surface of thefirst connection part 302 and the inclined surface of the secondconnection part 304 may have the same shape and size.

Also, the first connection part 302 may be connected and fixed to thefirst battery 110, and the second connection part 304 may be connectedand fixed to the second battery 120. For this, a first fixing part 342coupled to a portion of a circumferential portion of the first battery110 may be provided on an outer portion of the first connection part302, and a second fixing part 344 coupled to a portion of acircumferential portion of the second battery 120 may be provided on anouter portion of the second connection part 304. As illustrated in FIG.1, the first fixing part 342 may be provided on one surface, on whichthe first connection part 302 is provided, of both surfaces of the firstbattery 110, and the second fixing part 344 may be provided on onesurface on which the second connection part 304 is provided. Also, thefirst fixing part 342 may be coupled to the first lead 210 of the firstbattery 110, and the second fixing part 344 may be coupled to the secondlead 220 of the second battery 120. Also, although not shown in thedrawings, an adhesion material may be applied to at least a portion ofthe surface on which the first fixing part 342 and the circumferentialportion of the first battery 110 are coupled to each other. Also, theadhesion material may be applied to at least a portion of the surface onwhich the second fixing part 344 and the circumferential portion of thesecond battery 120 are coupled to each other.

The first connection part 302 and the second connection part 304 may berespectively connected to the first battery 110 and the second battery120. The inclined surfaces of the first connection part 302 and thesecond connection part 304 may contact each other to form a contactinterface. Also, an adhesion part 310 having adhesion force so that theinclined surface of the first connection part 302 and the inclinedsurface of the second connection part 304 adhere to each other may beformed between the first connection part 302 and the second connectionpart 304. In this specification and attached claims, even when theadhesion part is provided between the first connection part 302 and thesecond connection part 304, it should be interpreted that the inclinedsurfaces of the first connection part 302 and the second connection part304 may contact each other.

The first connection part 302 and the second connection part 304 may beelectrically connected to each other. Here, the electrical connectionmay mean that current flows between the first connection part 302 andthe second connection part 304. To electrically connect the firstconnection part 302 to the second connection part 304, the adhesion part310 may include a material having electrical conductivity.

As illustrated in FIG. 1, the current interrupt device 300 according tothe first example of the present invention may be generally providedbetween the first battery 110 and the second battery 120 to electricallyconnect the first battery 110 and the second battery 120 to each other.

When a portion or whole of the plurality of batteries constituting thebattery module is overcharged, the overcharged battery is swollen due tovaporization of the electrolyte and an increase in thickness of theelectrode assembly.

FIG. 2 is a perspective view illustrating a principle of interruptingcurrent by the current interrupt device according to the first examplewhen the battery module is overcharged.

Referring to FIG. 2, when the first battery 110 is swollen, the firstbattery 110 may apply external force from the first connection part 302toward the inclined surface of the first connection part 302. When thesecond battery 120 is swollen, the second battery may apply externalforce from the second connection part 304 toward the inclined surface ofthe second connection part 304.

When the external forces are applied toward the inclined surface of thefirst connection part 302 or the second connection part 304 by the firstconnection part 302 or the second connection part 304, if the appliedexternal force is less than predetermined force, the current interruptdevice 300 in addition to the first connection part 302 and the secondconnection part 304 may not be deformed. This is done because theadhesion force due to the adhesion part 310 exists between the inclinedsurface of the first connection part 302 and the inclined surface of thesecond connection part 304.

However, if the external force acting on the first connection 302 or thesecond connection part 304 is equal to or greater than predeterminedforce, it may be difficult to maintain the adhesion between the firstconnection part 302 and the second connection part 304 through only theadhesion force between the inclined surface of the first connection part302 and the inclined surface of the second connection part 304. Thus, asillustrated in FIG. 2, the inclined surface of the first connection part302 and the inclined surface of the second connection part 304 aredislocated with respect to each other, and thus, the first connectionpart 302 and the second connection part 304 are electrically interruptedwith respect to each other. Thus, the first battery 110 and the secondbattery 120 may be electrically interrupted with respect to each otherto stop an operation of the battery module 10.

FIG. 3 is a perspective view illustrating a second example of astructure of the current interrupt device in a state in which thebattery module normally operates according to the present invention.

According to a current interrupt device according to a second example ofthe present invention, if external force equal to or greater thanpredetermined force is applied to a first connection part 302 and asecond connection part 304, the inclined surface SL (see FIG. 4) of thefirst connection part 302 and the inclined surface of the secondconnection part 304 may be dislocated with respect to each other, andthus, the first connection part 302 and the second connection part 304may be electrically interrupted. In this point, the current interruptdevices according to the first and second examples of the presentinvention may be similar to each other. However, the current interruptdevice according to the second example of the present invention isdifferent from the current interrupt device according to the firstexample of the present invention in terms of a detailed configurationfor realizing the above principle. Hereinafter, the current interruptdevice according to the second example of the present invention will bedescribed with a focus on differences from the current interrupt deviceaccording to the first example of the present invention.

As illustrated in FIG. 3, the current interrupt device 300 according tothe second example of the present invention may include a pressing part320 disposed above or below the first connection part 302 and the secondconnection part 304 to press the first connection part 302 and thesecond connection part 304 downward or upward, respectively. Forexample, as illustrated in FIG. 3, the pressing part may be providedabove and below the first connection part 302 and the second connectionpart 304. The pressing part 320 disposed above the first connection part302 and the second connection part 304 may press the first connectionpart 302 and the second connection part 304 downward, and the pressingpart 320 disposed below the first connection part 302 and the secondconnection part 304 may press the first connection part 302 and thesecond connection part 304 upward. Here, the pressing part 320 may be aconstituent having elasticity. For example, the pressing part 320 mayhave a spring structure.

To press the first connection part 302 or the second connection part304, the pressing part may be supported by a different constituent. Forthis, the current interrupt device 300 according to the second exampleof the present invention may include a support part 330 supporting thepressing part 320 so that the pressing part 320 presses the firstconnection part 302 and the second connection part 304.

Here, as illustrated n FIG. 3, when the pressing part 320 is providedabove and below the first connection part 302 and the second connectionpart 304, the support part 330 may include a first support part 332provided below the pressing part 320 to support the pressing part 320provided below the first connection part 302 and the second connectionpart 304 and a second support part 334 provided above the pressing part320 to support the pressing part 320 disposed above the first connectionpart 302 and the second connection part 304.

FIG. 4 is a perspective view illustrating a principle of interruptingcurrent by the current interrupt device according to the second examplewhen the battery module is overcharged.

Referring to FIG. 4, when the first battery 110 is swollen, the firstbattery 110 may apply external force from the first connection part 302toward the inclined surface of the first connection part 302. When thesecond battery 120 is swollen, the second battery may apply externalforce from the second connection part 304 toward the inclined surface ofthe second connection part 304.

When the external forces are applied toward the inclined surface of thefirst connection part 302 or the second connection part 304 by the firstconnection part 302 or the second connection part 304, if the appliedexternal force is less than predetermined force, the current interruptdevice 300 in addition to the first connection part 302 and the secondconnection part 304 may not be deformed. This is done because thepressing part 320 presses the first connection part 302 and the secondconnection part 304 upward or downward so that static frictional forceacts between the inclined surface of the first connection part 302 andthe inclined surface of the second connection part 304.

However, if the external force acting on the first connection 302 or thesecond connection part 304 is equal to or greater than predeterminedforce, it may be difficult to maintain the contact between the firstconnection part 302 and the second connection part 304 through only thestatic frictional force between the inclined surface of the firstconnection part 302 and the inclined surface of the second connectionpart 304. Thus, as illustrated in FIG. 4, the inclined surface of thefirst connection part 302 and the inclined surface of the secondconnection part 304 are dislocated with respect to each other, and thus,the first connection part 302 and the second connection part 304 areelectrically interrupted. Thus, the first battery 110 and the secondbattery 120 may be electrically cut off to stop an operation of thebattery module 10.

FIG. 5 is a perspective view illustrating a third example of a structureof a current interrupt device in a state in which a battery modulenormally operates according to the present invention, and FIG. 6 is aperspective view illustrating a principle of interrupting current by thecurrent interrupt device according to the third example when the batterymodule is overcharged.

A current interrupt device 300 according to a third example of thepresent invention may have a structure in which the adhesion part 310 ofthe current interrupt device according to the first example of thepresent invention and the pressing parts 320 and the support part 330 ofthe current interrupt device according to the second example of thepresent invention are coupled to each other. In the current interruptdevice 300 according to the third example of the present invention,descriptions of an adhesion part 310, a pressing part 320, and a supportpart 330 are substituted for those of the current interrupt devicesaccording to the first and second examples of the present invention.

In the current interrupt devices according to the first to thirdexamples of the present invention, when the external force equal to orgreater than the predetermined force is applied, the inclined surface ofthe first connection part and the inclined surface of the secondconnection part may be dislocated with respect to each other tointerrupt the electrical connection between the first connection partand the second connection part. Thus, the magnitude of the externalforce when the electrical connection between the first connection partand the second connection part is interrupted may depend on the adhesionstrength of the adhesion part or the strength at which the pressing partpresses the first connection part and the second connection part.Particularly, when the pressing part has elasticity, the strength atwhich the pressing part presses the first connection part and the secondconnection part may depend on an elastic modulus of the entire pressingpart. Here, when the pressing part is provided in plurality, the elasticmodulus of the entire pressing part may be defined as magnitude of forcerequired to deform the entire pressing part provided in the currentinterrupt device by a unit length.

However, when the adhesion strength of the adhesion part or the elasticmodulus of the entire pressing part is too large in the currentinterrupt device according to the present invention, the external forceat which the electrical interruption occurs may be too large. As aresult, there is a problem in that safety of the battery module is notensured due to the fact that the electrical interruption does not occureven though the electrical interruption has to occur.

The swelling of the battery may occur not only in an overcharged statebut also a state in which the battery is stored at a high temperature.However, the battery is simply stored at the high temperature,possibility of ignition of the battery is low, and thus, theinterruption of the current may be unnecessary. However, if the adhesionstrength of the adhesion part or the elastic modulus of the entirepressing part is too small in the current interrupt device according tothe present invention, even when the battery or the battery module ismerely stored at the high temperature, the current interruption mayoccur, and a defective rate of the battery module may increase. Thus, tosecure the safety of the battery module and simultaneously minimize thedefective rate of the battery module, it is necessary that the adhesionstrength of the adhesion part or the elastic modulus with respect to theentire pressing part is properly set within a predetermined range whenmanufacturing the current interrupt device and manufacturing the batterymodule.

EMBODIMENTS

Hereinafter, the contents of the present invention will be described inmore detail through Embodiments and Experimental Examples. However,Embodiments and Experimental Examples are merely examples asillustrative purpose, and thus, the technical scope of the presentinvention is not limited thereto.

Embodiment 1

In Embodiment 1 of the present invention, a pressing part was used in acurrent interrupt device. An elastic modulus with respect to the entirepressing part was 3 kgf/cm.

The current interrupt device according to Embodiment 1 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates.

Embodiment 2

In Embodiment 2 of the present invention, a pressing part was used in acurrent interrupt device. An elastic modulus with respect to the entirepressing part was 5 kgf/cm.

The current interrupt device according to Embodiment 2 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Embodiment 2 are the same as those inEmbodiment 1.

Embodiment 3

In Embodiment 3 of the present invention, an adhesion part and apressing part were used together in a current interrupt device. Adhesionstrength of the adhesion part was 1 kgf/cm, and an elastic modulus withrespect to the entire pressing part was 1 kgf/cm. The adhesion strengthof the adhesion part is defined as force required when each of bothconstituents are stretched by a unit length on an adhesion surface whenboth the constituents are stretched after both the constituents adhereto each other.

The current interrupt device according to Embodiment 3 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Embodiment 3 are the same as those inEmbodiment 1.

Embodiment 4

In Embodiment 4 of the present invention, an adhesion part and apressing part were used together in a current interrupt device. Adhesionstrength of the adhesion part was 1 kgf/cm, and an elastic modulus withrespect to the entire pressing part was 3 kgf/cm.

The current interrupt device according to Embodiment 4 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Embodiment 4 are the same as those inEmbodiment 1.

Embodiment 5

In Embodiment 5 of the present invention, an adhesion part was used in acurrent interrupt device. Adhesion strength of the adhesion part was 2kgf/cm.

The current interrupt device according to Embodiment 5 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Embodiment 5 are the same as those inEmbodiment 1.

Embodiment 6

In Embodiment 6 of the present invention, an adhesion part and apressing part were used together in a current interrupt device. Adhesionstrength of the adhesion part was 2 kgf/cm, and an elastic modulus withrespect to the entire pressing part was 2 kgf/cm.

The current interrupt device according to Embodiment 6 was mounted in abattery module to manufacture the battery module. Then, the batterymodule was overcharged or stored at a high temperature to measurewhether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Embodiment 6 are the same as those inEmbodiment 1.

Comparative Example 1

In Comparative Example 1 of the present invention, a pressing part wasused in a current interrupt device. An elastic modulus with respect tothe entire pressing part was 1 kgf/cm.

The current interrupt device according to Comparative Example 1 wasmounted in a battery module to manufacture the battery module. Then, thebattery module was overcharged or stored at a high temperature tomeasure whether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Comparative Example 1 are the same asthose in Embodiment 1.

Comparative Example 2

In Comparative Example 2 of the present invention, a pressing part wasused in a current interrupt device. An elastic modulus with respect tothe entire pressing part was 7 kgf/cm.

The current interrupt device according to Comparative Example 2 wasmounted in a battery module to manufacture the battery module. Then, thebattery module was overcharged or stored at a high temperature tomeasure whether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Comparative Example 2 are the same asthose in Embodiment 1.

Comparative Example 3

In Comparative Example 3 of the present invention, an adhesion part wasused in a current interrupt device. Adhesion strength of the adhesionpart was 1 kgf/cm.

The current interrupt device according to Comparative Example 3 wasmounted in a battery module to manufacture the battery module. Then, thebattery module was overcharged or stored at a high temperature tomeasure whether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Comparative Example 3 are the same asthose in Embodiment 1.

Comparative Example 4

In Comparative Example 4 of the present invention, an adhesion part anda pressing part were used together in a current interrupt device.Adhesion strength of the adhesion part was 1 kgf/cm, and an elasticmodulus with respect to the entire pressing part was 5 kgf/cm.

The current interrupt device according to Comparative Example 4 wasmounted in a battery module to manufacture the battery module. Then, thebattery module was overcharged or stored at a high temperature tomeasure whether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Comparative Example 4 are the same asthose in Embodiment 1.

Comparative Example 5

In Comparative Example 5 of the present invention, an adhesion part anda pressing part were used together in a current interrupt device.Adhesion strength of the adhesion part was 2 kgf/cm, and an elasticmodulus with respect to the entire pressing part was 5 kgf/cm.

The current interrupt device according to Comparative Example 5 wasmounted in a battery module to manufacture the battery module. Then, thebattery module was overcharged or stored at a high temperature tomeasure whether the current interrupt device operates. The overchargingcondition of the battery module and the high-temperature storagecondition of the battery module in Comparative Example 5 are the same asthose in Embodiment 1.

Experimental Example 1

In Experimental Example 1, the battery modules manufactured according toEmbodiments 1 to 6 and Comparative Examples 1 to 5 were overcharged tomeasure whether the current interrupt devices interrupt current.

The overcharging conditions of the battery module are as follows. Thebattery module in which five batteries, each of which has a voltage of4.2 V when a state of charge (SOC) is 100%, are connected in series toeach other were overcharged by 50% so that the entire battery module hasa voltage of 31.5 V (4.2V*1.5). In a state in which constant currentflows when the battery module is overcharged, charging was performed forone hour.

Experimental Example 2

In Experimental Example 2, the battery modules manufactured according toEmbodiments 1 to 6 and Comparative Examples 1 to 5 were stored at a hightemperature to measure whether the current interrupt devices interruptcurrent.

The high-temperature storage conditions of the battery module are asfollows. In Embodiment 2, the battery module was charged so that thestate of charge (SOC) of the battery module is 100% and then was storedfor 8 weeks in a chamber at 60 degrees Celsius.

Experimental Example 1 and Experimental Example 2 were conducted on thebattery modules according to Examples and Comparative Examples, and theresults are shown in Table 1 below.

TABLE 1 Embodiment Comparative Example Classification 1 2 3 4 5 6 1 2 34 5 Experimental Interrupt Interrupt Interrupt Interrupt InterruptInterrupt Interrupt Not Interrupt Not Not Example 1 interrupt interruptinterrupt Experimental Not Not Not Not Not Not interrupt Not InterruptNot Not Example 2 interrupt interrupt interrupt interrupt interruptinterrupt interrupt interrupt interrupt

Referring to Table 1 above, the sum of the adhesion strength of theadhesion part and the elastic strength of the entire pressing part was 3kgf/cm, 5 kgf/cm, 2 kgf/cm, 4 kgf/cm, 2 kgf/cm, and 4 kgf/cm. Here, inthe current interrupt device according to Experimental Example 1, thecurrent interruption occurred, and in the current interruption device ofExperimental Example 2, the current interruption did not occur.

As described above, in the current interrupt device according to anembodiment, if the adhesion strength of the adhesion part or the elasticmodulus with respect to the entire pressing part is too large, theexternal force causing the electrical interception becomes too large. Asa result, the electrical interception does not occur even though theelectrical interception had to occur, and thus, the safety of thebattery module may not be secured. In the current interrupt deviceaccording to the present invention, if the adhesion strength of theadhesion part or the elastic modulus of the entire pressing part is toosmall, even when the battery or the battery module is merely stored atthe high temperature, the current interruption may occur, and thus, thedefective rate of the battery module may increase. However, in the caseof Embodiments 1 to 6, as shown in Table 1, it was confirmed that whenthe electrical interruption is required, the electrical interception isperformed to secure the safety of the battery module, and when thebattery module is in the high-temperature storage state, no failureoccurs in the battery module because the electrical interruption doesnot occur.

On the other hand, in the case of Comparative Examples 1 and 3, theadhesion strength of the adhesion part or the elastic strength withrespect to the entire pressing part was 1 kgf/cm. In this case, inExperimental Example 1, it was confirmed that although the safety of thebattery module is ensured by the occurrence of the electricalinterruption, even if the battery module is in the high-temperaturestorage state, the battery module is defective by the occurrence of theelectrical interruption.

Also, in the case of Comparative Examples 2, 4, and 5, each of theadhesion strength of the adhesion part or the elastic strength withrespect to the entire pressing part was 7 kgf/cm, 6 kfg/cm, and 7kfg/cm. In this case, in Experimental Example 2, it was confirmed thatwhen the battery module is in the high-temperature storage state, thebattery module isn't defective due to no electrical interruption, but inExperimental Example 1, the safety of the battery module is not ensureddue to no electrical interruption in the overcharged state.

Thus, in the current interrupt device according to the presentinvention, it is confirmed that when the sum of the adhesion strength ofthe adhesion part and the elastic strength of the entire pressing partis 2 kgf/cm to 5 kgf/cm, the safety of the battery module is ensured,and the problem of the failure of the battery module is solved.

While the embodiments of the present invention have been described withreference to the specific embodiments, it will be apparent to thoseskilled in the art that various changes and modifications may be madewithout departing from the spirit and scope of the invention as definedin the following claims.

1. A current interrupt device comprising: a first connection part havingone surface on which an inclined surface is formed; and a secondconnection part having one surface on which an inclined surface having ashape corresponding to the inclined surface of the first connection partis formed, wherein the inclined surface of the first connection part andthe inclined surface of the second connection part contact each other toform a contact interface, the first connection part and the secondconnection part are electrically connected to each other, and when anexternal force equal to or greater than a predetermined force is appliedto the inclined surface of the first connection part or the inclinedsurface of the second connection part, the inclined surface of the firstconnection part and the inclined surface of the second connection partare dislocated with respect to each other on the contact interface tointerrupt electrical connection between the first connection part andthe second connection part.
 2. The current interrupt device of claim 1,further comprising an adhesion part disposed on the contact interface sothat the inclined surface of the first connection part and the inclinedsurface of the second connection part adhere to each other.
 3. Thecurrent interrupt device of claim 1, further comprising a pressing partdisposed above or below the first connection part and the secondconnection part to press the first connection part and the secondconnection part downward or upward, respectively.
 4. The currentinterrupt device of claim 3, further comprising a support partsupporting the pressing part so that the pressing part presses the firstconnection part and the second connection part.
 5. The current interruptdevice of claim 1, further comprising an upper pressing part disposedabove the first connection part and the second connection part thatpresses the first connection part and the second connection partdownward, and a lower pressing part disposed below the first connectionpart and the second connection part that presses the first connectionpart and the second connection part upward.
 6. The current interruptdevice of claim 1, further comprising a first fixing part disposed on anouter portion of the first connection part so that the first connectionpart is configured to be coupled to a portion of a circumferentialportion of a first secondary battery and a second fixing part disposedon an outer portion of the second connection part so that the secondconnection part is configured to be coupled to a portion of acircumferential portion of a second secondary battery.
 7. The currentinterrupt device of claim 2, further comprising a pressing part disposedabove or below the first connection part and the second connection partto press the first connection part and the second connection partdownward or upward, respectively, wherein the sum of adhesion strengthof the adhesion part and an elastic modulus of the pressing part is 2kgf/cm to 5 kgf/cm.
 8. A battery module comprising: a first battery; asecond battery spaced apart from the first battery; and a currentinterrupt device disposed between the first battery and the secondbattery, wherein the current interrupt device comprises: a firstconnection part having one surface on which an inclined surface isformed; and a second connection part having one surface on which aninclined surface having a shape corresponding to the inclined surface ofthe first connection part is formed, wherein the inclined surface of thefirst connection part and the inclined surface of the second connectionpart contact each other to form a contact interface, the firstconnection part and the second connection part are electricallyconnected to each other, and when an external force equal to or greaterthan a predetermined force is applied to the inclined surface of thefirst connection part or the inclined surface of the second connectionpart, the inclined surface of the first connection part and the inclinedsurface of the second connection part are dislocated with respect toeach other on the contact interface to interrupt electrical connectionbetween the first connection part and the second connection part.
 9. Thecurrent interrupt device of claim 3, wherein the pressing part is aspring.